The present invention concerns an orthosis of the lower limb, and more particularly an orthosis enabling walking and furthermore enabling total freedom of the foot.
Rigid ortheses of the lower limb which maintain the knee permanently in the same position of extension are already known. In such cases, walking and standing are possible, but sitting is possible only after removal of the orthosis.
Ortheses hinged at the level of the knee are also known. They are fitted with a lock enabling the knee to be blocked in the extension position to enable walking or standing with a stiff leg. Sitting is possible without removing the orthosis on the leg by release of the lock.
Other ortheses exist with a thigh piece and a legging hinged together at the level of the knee. They are fitted with elastic return devices enabling the leg to be brought back to the extension position. These elastic return devices enable the wearer to have a gait that is more flexible that in the case of rigid ortheses, but as the elastic devices are arranged in the direction of extension, sitting is possible only when the wearer removes or releases them.
The document FR-A-2 599 246 describes an orhtosis hinged at the level of the knee which enables the wearer to stand and walk without any manipulation, given that the knee is assisted elastically both in extension and in flexion.
French patent application FR 94 07 694 describes an orthosis of the lower limb comprising a thigh piece and a legging hinged together at the level of the knee, the articulation on the thigh piece being formed by a hinged assembly including at least one pair of rods arranged laterally with respect to the knee on at least one side. The pair of rods includes a front rod and a rear rod which are each hinged, on the one hand, on the thigh piece, and on the other hand, on the legging, the intersections of the lines corresponding to each pair of rods defining an instantaneous axis of rotation. A tensor is arranged laterally on at least one side between an anchoring point integral with the thigh piece and an anchoring point integral with the legging.
The known devices, at the level of the junction of the foot with the leg, are either rigid or flexible. When they are rigid, they enable walking, by their rigidity, but do not provide flexibility of the unipodal support to enable, for example, the driving of a car. When they are flexible, for example when they include elastic levators such as a piano wire, a compression spring, or rubber added to a trunnion-mounted device, they fail to offer sufficient rigidity to ensure safe walking as there is no stabilizing effect on the knee. Moreover, the known devices do not enable any rotation of the unipodal support around the vertical axis. The aim of the present invention is, therefore, to overcome these disadvantages.
An initial aim of the present invention is to provide an orthosis capable of going from a rigid state to a flexible state, in order to enable, alternately, safe walking and freedom of the unipodal support in rotation around to the vertical axis, and control of rotations in walking. Another aim of the invention is to provide an orthosis capable of going from the rigid state to the flexible state simply and practically.
The invention thus concerns an orthosis comprised of a unipodal support, a vertical rod which may be rigid, a cuff enabling the fixing of the orthosis to the calf, the unipodal support being connected to one end of the vertical rod and the cuff being connected to the opposite end of the vertical rod. The orthosis is such that the unipodal support is connected to one end of the vertical rod by means of a flexible cylindrical sleeve enabling the horizontal rotation of the unipodal support around the vertical rod, i.e., rotation around a main longitudinal axis of the vertical rod, and the vertical rotation of the unipodal support around the vertical rod, i.e., rotation around an axis perpendicular to the main longitudinal axis of the vertical rod, and that it includes a cylindrical bushing force-fitted on to the elastic sleeve so as to block in at least one direction the vertical rotation of the unipodal support around the vertical rod without blocking the horizontal rotation of the unipodal support around to the vertical rod.
According to one characteristic of the invention, the sleeve is a core-less cylinder in flexible material including a fastening at each end, these fastenings being independent of each other.
According to another characteristic of the invention, the sleeve includes a rigid base in which the bushing meshes. Advantageously, the sleeve and the bushing have corresponding diameters. Preferably, the bushing has an inside diameter equal to the outside diameter of the rigid base, to within the necessary tolerances, so that the bushing meshes with the base. Provision can be made for the longitudinal axis of the unipodal support to form an angle with the axis of symmetry of the cuff so that the vertical axis is situated laterally outwards in relation to the wearer.
According to yet another characteristic of the invention, the vertical rod may consist of a flexible foil, hollowed in the center, to enable the fitting of a reinforcement so as to increase or decrease the rigidity of the rod when the bushing is in position in the base, and the sleeve may be made of natural or synthetic rubber.
According to one mode of implementation, the bushing is raised to enable a vertical rotation movement of the unipodal support around to the vertical rod.